2D Microscale Observations of Interlaminar Transverse Tensile Fracture in Carbon/Epoxy Composites

This study presents a new experiment to image and analyze the evolution of transverse tensile fracture in tape-laminate carbon/epoxy composites at the microscale. To this end, a miniature double cantilever beam specimen is developed to produce stable transverse tensile fracture and various amounts of crack turning through a stack of 90° plies. The specimen is wedge-loaded with a custom micromechanical tester, while the crack growth is optically monitored at both the micro- and macro-scale. Post-test, microscale images are analyzed to determine the transverse crack path relative to the applied loading, and to directly measure local strains using 2D digital image correlation. The experimental data sets obtained in this study enable direct validation of finite element simulations of transverse tensile cracking in fibrous composites at the microscale and provide impetus for their further model development.